\begin{tikzpicture}
    \tkzDefPoints{0/0/B,  2.5/0/C, 3.3/1.5/D, 0.8/1.5/A}
    \tkzInterLL(A,C)(B,D)  \tkzGetPoint{O}
    \tkzDefMidPoint(O,A)  \tkzGetPoint{M}
    \tkzDefMidPoint(O,C)  \tkzGetPoint{N}
    \tkzDrawPolygon(A,B,C,D)
    \tkzDrawSegments(A,C  B,D  B,M  D,N)
    \tkzLabelPoints[left](A,B)
    \tkzLabelPoints[right](C,D)
    \tkzLabelPoints[above right=-0.4em](M)
    \tkzLabelPoints[below left=-0.4em](N)
    \tkzLabelPoints[above](O)
\end{tikzpicture}

